Automatic toaster



Sept. 5, 1939. R. sARDESoN AUTOMATIC TOASTER Filed Feb. 19, 1938 2 Sheets-Sheet 1 Invlentor' Fobert sordeson. MM

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Sept. 1939. R. sARDEsoN I QWYQ@ AUTOMATIC TOASTER Filed Feb'. 19, 1938 2 SweS-Sht 2 Fig-3 @E ifi/ awww.

Patented Sept. 5, 1939 UNITED STATES PATENT OFFICE AUTOMATIC TOASTER Robert Sardeson, Minneapolis, Minn., assignor to McGraw Electric Company, Chicago, lll., a corporation of Delaware Application February 19, 1938, Serial No. 191,485

10 Claims. (Cl. 219-19) My invention relates to cooking devices and particularly to automatic electric toasters.

The main object of my invention is to provide an automatic electric toaster having a thermally controlled timing mechanism to determine the duration of a toasting operation, said timing mechanism embodying a manual and a thermal control means acting on the timing mechanism to cause it to properly contrl the duration of a.

toasting operation irrespective of different energizing voltages applied to the toaster, to thereby obtain uniform toasting of successive slices of bread.

Another object of my invention is to provide a thermally controlled mechanical timer assembly for an automatic toaster that shall permit of making light toast when the heating elements are energized from a high voltage circuit and oi making dark toast when the heating elements are energized from a low voltage circuit.

Other objects of my invention will either be apparent from the following-description when taken in connection with the drawings accom-- panying the same or will be set forth in the specification and particularly in the appended claims.

In the drawings,

Fig. l is a view in vertical longitudinal section through a toaster embodying my invention. taken on the line I-l of Fig. 3,

Fig. 2 is a view in vertical longitudinal section through a toaster embodying my invention taken on the line 2 2 of Fig. 3,

Fig. 3 is a fragmentary view in horizontal section taken on the line 3-3 of Fig. l,

Fig. 4 is a fragmentary view in side elevation showing the manually and thermally controlled timing mechanism in one of its operatiive positions, Y

Fig. 5 is a fragmentary view similar to Fig. 4

but showing the manually and thermally controlled timing mechanism in another of its oplerative positions,

Fig. 6 is a fragmentary enlarged vertical sectional view taken on the line 6-6 of Fig. 5,

Fig. 'l is a fragmentary enlarged view in vertical section taken on the line 1-1 of Fig. 8, and,

Fig. 8 is an enlarged view in horizontal section taken on the line 8--8 of Fig. 5.

The general details of the vertical oven-type toaster designated generally by numeral ll have been described in several earlier applications filed by the present inventor and therefore only such detailed description thereof will be given as is necessary to set forth the general details o f the particular form of automatic electric toaster with which the device more particularly embodying my invention is shown.` Reference may here be made to my copending application Serial No. 136,826 iiled April 14, 1937, and assigned to the 5 same assignee as is the present application for such details.

The toaster assembly Il includes a skeleton base I3 which may be made of molded composition material having secured thereto at its upper 10 edge a bottom plate I 5- which may be made of thin sheet metal material and which may have a number of longitudinal openings therein corresponding in number to the number of bread slice supportsembodied in the toaster. One of these l5 openings is shown for instance at I1 in Fig. 2 of the drawings. It is to be noted further that while I have shown a two-slice toaster .in the drawings, my invention is not limited thereto but is applicable to a toaster adapted to smulta- 20 neously operate on any number of slices of bread.

The toaster assembly includes further a plurality of vertically extending electric heating elements, here shown as four in number, each com- 25 prising one or more sheets of mica I9 on which are positioned wires or strips 2l of suitable resistor material. The bottom edges of the respective sheets of mica l9 may be held by bentup lugs 23 constituting a part of the bottom plate 30 l5. The upper ends of the respective sheets of mica I9 may be held by top frame plates 25 of which two are used in the structure shown in the drawings, guard wires 21 being suspended from the respective side portions of the top frame 35 plates and having return bent portions at their upper ends to engage with the upper edges of the mica sheets all in a manner now well known in the art. The assembly includes further a casing 29 comprising front, rear and side walls and a 4o cover member 3l all of which are now known in the art.

A pair of bread slice supports 33 are vertically movable in the toaster, each bread slice support being positioned between two spaced heating ele- 45 ments and movable from an upper non-toasting position to a lower toasting position in a manner well known in the art.

Means for movably supporting the bread slice supports may include a plurality of standards 50 35, 36 and 31 which are positioned in the front end portion of the toaster structure there being an intermediate wall 39 provided adjacent the front edges of the respective heating elements.

A rear intermediate wall 4| is also provided as 55 well as two baille plates 43 spaced laterally from the outermost heating elements. The front intermediate wall 39 and rear intermediate wall M and the two outermost heating elements constitute the vertical walls of a cooking or toasting chamber the bottom plate Il constituting a bottom closure therefor and the cover Il constitutto the front end portion of right-hand bread slice support 33. A slider 41 is Amovably mounted on standard and is similarly connected to the front end portion .oi' the left-hand bread slice support 3l, the front end portiony oi these supports extending through iront intermediate wall Il in a manner well known in the art. 'A horizontal rod n' may be provided 4to maintain'the two bread slice supporta in properly spaced position relatively to each other as well as to provide l a rigid connection between the respective sliders and the bread slice supports. A carriage Il is movably mounted on standard 3i and may move upwardly independently of the two sliders 4l and 41 but when moved downwardly by an operator pressing on a knob 53 outside o! the casing, will cause downward movement of the two sliders and therefore of the bread slice supports.

Switching means iorcontrolling the energization oi' the plurality of heating elements includes a ilxed contact member 5l insulatedly supported on iront intermediate wall 3l and a contact arm 51 also insulatedly mounted on the iront intermediate wall as on a bracket il. yA' bellcrank lever pivotally mountedat Il Aon the rear intermediate wall Il included a depending short arm 63 to the lower end oi which there is connected one end of a biasing spring I5 the other end oi' which is connected to the iront part oi' bottom plate IB. A longer arm 61,01' the bellcrank lever extends forwardly through a slot in the front intermediate wall 39 and has a slot 8! therein at its front end into which slot thecentral portionof rod 49 may nt so that when knob 53 is moved downwardly by an operator arm 81 will be turned in a clockwise direction, as seen in Fig. 2 of the drawings.

Slider 41 on standard 35 has a vertical plate 1| secured thereto which plate has an angularly extending slot 13 therein. The upper en d of contact arm 51 has a laterally extending rod 14 secured thereto which pin moves in slot 13. The construction is such that upondownward movement o! knob 53 carrying with it the bread slice supports 3l into their downward or toasting position slotted plateJl is also moved downwardly and causes closing movement of contact arm 51 all in a manner well known in the art. A rear carrying knob 15 may -be provided and a twin conductor cable. 11 may be brought out through an insulating blushing 19 in the rear walloi' the outer casing to permit of connecting the toaster and particularly its heating elements to a source ol supply of electric current.

'Ihe toaster assembly includes also a mechanical timer assembly 8l which is shown as of the type disclosed and claimed in Ireland Pat. No. 1,866,808. It 1s thought unnecessms7` to go into details as to this structure since it is now well known in this art and rei'eren'ce will be made only to Fig. 'l oi the drawings where a gear wheel I3 is shown as driving a pinion 85 having ilxedly mounted thereon a crank pin or eccentric t1 which is movable in the upper slotted end of an oscillator 89, the lower end of which engages the straight end oi' a coil spring -9I, the other end oi' this spring being operatively connected with a balance wheel 93. The oscillator 89 is pivotally mounted on and adJustably supported by a lever arm 95, which lever arm is rigidly mounted on a shaft 81 which is supported 'by the timer assembly and more particularly by the side plates thereof. A biasing spring 99 is being provided to hold the oscillator'in that position which will result in the slowest speed of operation oi' the timer thereby providing a relatively long duration oi.' operation oi' the timer.

It may be here noted that the-carriage Il is provided with a lateral extension Ill (see Figs. l and 3), the lower edge portion of this extension being of inverted V-shape and adapted to engage a pin |03 extending laterally from a rack bar Il! to thereby cause winding up of the me` chanical timer simultaneously with the movement oi' the bread slice supports in to toasting position and closing of the circuit controlling switch for the heatingl elements.

Ii' the knob 53 is released by an. operator immediately after it has been moved to its lowermost position the timing mechanism will unwind causing an upward movement oi' the carriage and member lill, which member is so shaped at its upper edge (see Fig. l) that it can engage withthe upper end of a latch arm |88 and move the same so that its lower end portion I |I1 may be moved out of engagement with a part |08 on right-hand slider l5, the interengagement of vmembers |01 and |09 holding the two sliders Vand the bread slice supports in their'lowered position and the switch in closed position during a toasting operation. Toasters oi' this general kind may be operated under a variety of conditions particularly as concerns the voltage of the electric circuit to which they are connected. While in most cases the operating-voltage available is on the order of 115 volts. relatively higher voltages may be encountered at times, these voltages ranging up to 122 volts. It is also vpossible for a toaster of this kind to be connected to a circuit o! extremely low voltage because oi' some abnormal condition as to load bution circuit and as an extreme case of low voltage, cases have been found where thisv energizing voltage was on the order of 95 volts.

In addition to this, toasters o'f this general kind are designed and constructed so that it is possible to obtain light" toast, that is toast that has been only slightly dlscolored, as well as "dark toast, that is where the slice of bread has been toasted to a dark surface color. It is of course desirable to be able to obtain light toast when the toaster is energized from a high voltage circuit as well as to obtain dark toast 0n necessary that the duration of a toasting operation berelatively short while a much longer duration of a toasting operation is required if a dark piece oi toast is desired.- The elements now to be described in detail permit of obtaining any desired degree of toasting on either low, average or high voltage.

A manually actuable knob HI is located at the lower iront and side portion of the toaster casing and is mounted on the same shaft which carries a pinion HI, this shaft being supported in a bearing member III. The pinion H3 meshes with the er toothed end portion of a bracket H1 which'bracket is of generally L-shape and on a relatively long distri- -may move vertically against the outer side plate of the timing mechanism. The bracket is held against the outer surface of the side plate by a bowed spring Il! interfltting with pins |2|l j in -a manner now well known in the art.

"A resilient stop |22 is mounted on and sup- |25 is flxedly mounted onvshaft Hand has an ported by the bracket ||1 and extends in a substantislly horizontal position adjacent the outer surface of the right-hand side plate of the timer. as seen from the front of thetoaster. An arm outer end portion projecting from the substantially straight intermediate portion to engage the lower surface of the resilient stop member |22 substantially as shown in Figs. 1, 4 and 5.

'Ihe thermal control member includes a himetal bar |21 which comprises a longer main portion and a shorter compensating portion, vthe outer or free end. of the shorter ieg being secured to an end portion |29 of the 'bracket The particular details of a bimetal thermostat of this vkind are disclosed and claimed-in my copending application Serial No. 130,287 filed March 11, 1937 and assigned to the same assignee as is the Y present application. A cam member |I| oi' generally bar shape has one of its ends secured to the free end of the longer leg of the thermostat. this cam arm extending forwardly of the bimetal thermostat and being adapted to engage with a laterally extending lug |32 bent out of the general plane of arm |25. It will be noted that the point of engagement of arm |25 and member |23 is substantially at the outer end of arm |25 while the point of engagement of cam arm |3| with the single arm speed adjusting lever |25 is at a point intermediate its ends, at lug |23.

Spring 89 tends, as has already been set forth hereinbefore, to bias the oscillator to its slow speed position and the outer end of arm |25 will therefore be continuously in engagement with the lower surface of the resilient arm |22. Turning movement of knob in one direction will cause downward movement of bracket li'l and of member |23 thereby causing turning movement of arm |25 in a clockwise direction (as seen in Figs. l, 4V and 5) whereby the `speed of operation of the timing mechanism may be increased by manuallyl actuable means.

.motion varying with the manually-effected set- When the toaster is operatedy and the heating elements are energized the forward end of the longer leg' of bimetal thermostat |21 moves downwardly,thereby moving cam bar |3| downwardly or-in a counterclockwise direction as seen in Figs. l, 4 and 5. There is. therefore. a lost -motion connection between the cam bar and the speed adjusting lever. the amountof this lost ting of the bracket ||`l.

Fig. 5 of the 4drawings illustrates the position' of bracket ||1 and of' arm |25 when dark toast is desired and when operating on a low voltage. It will be noted that bracket ||1 is in substan tially its uppermost .position land the distance between lug |33 and the bottom edge of cam bar lli (which is shown inthe position which it oc particularly that the distance between the bottomofthe cambar |2| andlug Illismu'chless than the distance'between these two parts -when in the positions shown in Fig. 5 of the drawings. The designand construction ot the thermally actuable controlling means including the bimetal thermostat and the cam bar is such that the thermostat is deflected enough during the rst cycle of operation, starting with a cold toaster, to act upon the speed control lever |25 and thereby cause speeding up ofthe timing mechanisml and a shortening of the duration of the operating period. When it is desired to obtain a dark piece of toast on low voltage, it is necessary that the duration of the operating period be relatively long and this may require a duration on the order of three and one-half minutes or possibly even slightly longer. It is therefore desirable that the cam surface does not engage with thespeed control lever |25 until at a relatively late instant of time in the operating period and this resultis obtained by making the distance between the cam bar |3| and the lug |22 relatively great by operation of the manually actuable adjusting means to move the parts tothe positions shown in Fig. 5 of the drawings.

Ifanoperatorshoulddesiretoobtainarelatively light piece of toast on a high voltage energizing circuit it is necessary that the parts be first adjusted manually to the positions shown in Fig. 1 o1' the drawings to start the timing mechanism at a relatively'high speed and to then cause the thermally actuable cam bar lli to engage the speed adjusting lever relatively earlier in the course of an operating period so that the duration of an voperating period may -be on the order of forty-live seconds when thetoaster assembly has attained- -its maximum operating temperature` It will be noted that the temperature varition necessary to cause the cam bar to actually engage the speed adjusting lever is much less than wasthe case when the parts were in the position shown in Fig. 5 of the drawings.

Tests on a toaster structure of this kind have shown that' the lug |33 may be so located between the ends of the speed adjusting lever that voltages varying from-95 volts to 120 or even 122 volts. This result is possible even' though the' length of time elapsing between successive operating periods varies from a very few seconds to lengths of time on the order of a minute, iive minutes 'or more. 'Ihe function of the hump near the end of resilient member |22 is to ensure that the change in the lostvmotion relationship between the cam bar |3| and the speed changing lever arm |25 would be other than a straight line, whereby a more uniform toasting eil'ect with varying supply circuit voltage is obtained.

found to operate in the desired manner tc attain .'Ihe device embodyingmy invention has been I the objects set forth hereinbeiore and it may be amount of movement of the manually actuable means.

While I have villustrated and described a particular kind of encased or oven-type toaster, I desire it to be understood that my invention is not limited to such particular details of construction but that it may be applied to other forms of toasters. It is to be understood also that changes may be made in the particular details of construction of the thermally and manually controllable timing mechanism as will be covered by the appended claims which are to be limited only by the prior art.

I claim as my invention:

l. An automatic electric toaster comprising a heating element, means to initiate a toasting operation and means to terminate a toasting operation, said terminating means including a variable speed mechanical timer having a single arm lever pivotally mounted thereon and connected to change the timer speed when turned, a manually-movable means having resilient engagement with said lever and a thermallyactuable means mounted on and movable with said manually-movable means and spaced from said lever arm at normal'temperature, the space between the thermally-actuable means and the lever arm at constant temperature decreasing -with manually-effected movement of the lever in a timer-speed-increasing direction.

2. In an automatic toaster, the combination with a heating element for toasting a slice of bread and a variablgspeed mechanical timer means for terminating the toasting of a slice of bread, of a lever arm `connected with said rnechanical timer to cause a change of speed thereof when the lever arm is turned, means to bias said lever arm in a timer-speed-reducing direction, a manually-movable means acting on said lever arm to cause turning movement thereof, a spring bar carried by the manually-movable means and engaging said lever arm to provide a resilient .cushioning and noise-reducing connection be- 3. An automatic electric toaster comprising a heating element subjectable to different voltages, means to initiate a toasting operation and means to terminate a toasting operation, said terminating means including a variable speed mechanical timer having 'a pivotally mounted lever arm thereon and connected therewith to cause a change in speedy of the timer when turned, means to bias the lever arm in a timer-speed-reducing direction, a manually-movable means for acting on said lever arm to increase the initial speed of the timer when the toaster is to operate at a relatively high voltage, a spring bar carried by said manually-movable means engaging said lever arm to provide a. cushioning and noisereducing connection therebetween, and a thermally-actuable means effective when heated to act on said lever arm to cause an increase in timer speed, said movable and said thermallyactuable means acting on said lever arm. so that a given increase of temperature of the thermally-actuable means above room temperature causes a greater increase in timer speed when said timer is manually adjusted for toaster operation at higher voltage than when manually adjusted for operation at lower voltage.

4. In an automatic toaster, the combination with a heating element for toasting a slice of bread and a variable speed mechanical timer means for terminating the toasting of a slice of bread, of a. lever arm iixedly pivotally mounted at one of its ends on said mechanical timer and connected with said timer to cause a change of speed thereof when the lever arm is turned, a manually-actuable means engaging said lever arm at one point thereof for causing turning movement thereof and a thermally-actuable means supported solely by said timer and mounted on said manually-movable means and effective when heated to engage said lever arm at another point thereon for causing turning movement thereof.

5, In an automatic toaster, the combinationl with a heating element for toasting a slice of bread and a variable speed mechanical timer means for terminating the toasting of a slice of bread, of a lever arm flxedly pivotally mounted at one of its ends and connected with said mechanical timer to cause a change of speed thereof when the lever arm is turned, a manuallyactuable member supported solely by said timer and a plurality of separate means mounted on and supported solely by said manually-actuable member for causing turning movement of said speed changing lever arm and engaging said lever arm in such manner, that substantially similar degrees of movement of the respective means cause different degrees of turning movement of said lever arm.

6. In an automatic toaster, the combination with a heating element for toasting a slice of bread and a variable speed mechanical timer means for terminating the toasting of a slice of bread, of a lever arm ixedly pivotally mounted at one of its ends on said timer and connected therewith to cause a change of speed thereof when the lever arm is turned, a manuallymovable means acting on said lever narm to cause turning movement thereof, the extent of such turning movement being substantially the same as the extent of movement of said manuallymovable means and a thermostat mounted and supported solely on said manually-movable means and normally free of -any mechanical stress, said thermostat being eifeetive when heated to act on said lever arm to cause turning movement thereof, the extent of such turning movement being greater for agiven extent of movement of said thermostat than would result from the same extent of movement of the manually-movable means.

7. In an automatic toaster, the combination with a heating element for toasting a slice of read and a variable speed mechanical timer means for terminating the toasting of a slice of bread, of a lever arm xedly pivotally mounted at one of its ends on said timer and connected therewith to cause a change of speed thereof when said lever is turned, a manually-actuable means on said timer acting on said lever arm to cause turning movement thereof, a thermallycontrolled means supported solely by said timer and mounted on and movable with said manually-actuable means, out of any operative engagement with and spaced a given distance from said lever arm at room temperature and effective when heated beyond a predetermined temperature to engage and turn said lever arm to cause an increase of speed of the timer, said manually-actuable means being eiective when moved in timer-speed-increasing direction at a constant temperature to reduce the distance between the thermally-controlled means and its point of engagement with said lever arm.

8. A n automatic electric toaster comprising a heating element subjectable to different supply circuit voltages, means to initiate a toasting operation and means including a variable speed mechanical timer having a lever arm xedly pivand said thermally-actuable means acting on` said lever arm so that'a given increase of temperature of the thermally-actuable means above room temperature causes a greater increase in timer speed when said timer is manually adjusted for toaster operation at higher voltage than when manually adjusted for operation at lower voltage.

5 I 9. A device as set forth in claim 6 and including a spring bar carried by the manually-movable means and engaging said lever arm, said spring bar providing a resilient cushioning and noise-reducing connection between the manually-movable means and the lever arm,

l0. An automatic electric toaster comprising a heating element subjectable to different voltages, means to initiate a toasting operation and means to terminate a toasting operation, saidtermlnating means including a Variable speed mechanical timer having a lever arm fixedly pivotally mounted at one of its ends thereon and connected therewith to cause a change in timer speed when turned, means to bias said lever arm in a speed-reducing direction, a manuallyactuable means on saidtimer having a spring bar thereon engaging said lever arm at a point a given distance away from said pivotally mounted end, and a thermally-actuable means supported solely by said timer, supported solely by and movable with said manually-actuatable means and normally out of engagement with saidlever arm and eiective when heated to operatively engage said lever arm at a. point intermediate its ends.

ROBERT SARDESON. 

